Btjdolf hase



Apr. 3,` 1923 3,450,439

R. HASE RECORDING PHONOGRAPH Filed Feb. 18, 1921 Patented Apr. 3, 1923.

UNITED STATES PATENT OFFICE.

RUDOLF HASE, OF BERLIN, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TONAMLOOZE VENNOOTSCHAP FINANZIEELE MATTSCHAPIJ DRIEBERGEN, OF AMSTERDAM,NETHERLANDS, A COMPANY OF NETHERLANDS.

RECORDING PEONOGRAPH.

Application filed February 18, 1921.

To all, cli/wm 'it 11m/y 0011.061111.'

Be it known that l, RUDOLF Hasn, citi- Zen ot the German Republic,chief` engineer, residing at Friedrichstrasse 24C, Berlin, SV. 48,Germany, have invented new and useful Improvements in RecordingPhonographs (on which application has beeninade for Letters Patent inGermany No. T. 23,608 IX/412g, liled` 6th February, 1920; Switzerland,Nov. 15th, 1920; Austria, November 16th, 1920; CZecho-SlovakianRepublic. Nov. 19th, 1920; Hungary, November 19th, 1920; Poland,November 23d, 1920; Netherlands, November 25th, 1920; Finland, November30th, 1920; France, December 1st, 1920; Belgium, December 3d, 1920;Sweden, December 1th, 1920; Great Britain, December 21st, 1920), ofwhich the following is a speciiication.

The invention relates to phonographic apparatus, in whichgspeech isrecorded by the aid of an electromagnetic sound-box, and its purpose isto record speech automatically without the immediate co-operation, andeven if desired without the knowledge, of the speaker. For this purposeaccording to the invention the electromagnet of the sound box isconnected with a sensitive microphone adapted to pick up sound wavesarising in its neighborhood, and automatically to transmit correspondingcurrent-oscillations to the recording sound-box. The use of aphonographic recorder in combination with such a sensitive microphonefor purposes of dictation offers the advantage that the dictation iscompletely unrestrained, since the speakers thoughts are not divertedby` the necessity of speaking into the mouthpiece of an ordinarymicrophone or or" a speaking-tube, but he can speak quite naturallywithout reference to the apparatus, as if dictating to ashorthand-typist. As is described in more detail below by the use of asensitive microphone (herein called a listening microphone) as thesound-receiver for the recording apparatus, conversations even betweenseveral parties can be recorded without any restraint upon the speakers.The driving mechanism may be put in action by an electromagneticallyreleased time-lag device, so that the circuit which causes the apparatusto start need only be closed momentarily, which can be done withoutattracting attention. Finally recording may be made com- Serial No.446,202.

pletely automatic by providing in the circuit of the listeningmicrophone a switch device actuated by'the speaking current, andcontrolling the time-lag device, so that the apparatus works so long asspeech continues.

In the drawings two forms of construction according to the invention areillustrated diagrammatically; Figure 1 being the simple construction inwhich the driving mechanism is set going by hand, while in Figure 2 isshown the device Jfor automatic actuation.

The record surface is a cylinder 1, with which a recording sound-box 2is associated in known manner. F or the sake of simplicity the remainingparts of the apparatus, which are unaffected by the present invention,are not illustrated. The driving mechanism 3 is indicated as an electricmotor, but may be any electrically controlled motor as an electricallyreleased clock-work. l indi-- Cates the listening microphone which maybe o'fany desired construction; by way of er:- ample it is assumed to bedivided into several cells indicated by the small circles 5. It isconnectedl with the electron'iagnet S of the sound-box 2 by leads 6, 7extending to the recording apparatus; a battery 9 is included in thecircuit to supply the micron phone 4. rlhe circuit of the` motor 3 canbe closed by a switch 10 located in the neighborhood of the listeningmicrophone 1. The microphone will generally be inconspicuously arranged,but in as favourable a position as possible for the sound waves toimpinge on it; while the` switch 10 may be so placed that it can be usedby the possessor of the device unnoticed by a visitor whose conversationis to be recorded. There may also be associated with the switch 10 acontact in the microphone circuit, so that current is taken from thebattery 9 only while the recorder is working. When conversation is to berecorded the switch 10 is closed, whereupon the motor 3 starts up andsets the cylinder 1 and the traversing mechanism of the sound-box 2 inmovement. The sound waves arising from the conversation impinge upon themicrophone cells 5, and the conversation is recorded.

It is desirable to put the motor 3 in circuit, not immediately by theswitch 10, but through an electromagnetically actuated time-lag device11 (Fig. 2). The advantage of this is that the switch 10 need not beclosed continuously, and the record of the conversation can be brokenoff without of necessity attracting the visitors attention bymanipulation, which cannot wholly be concealed, for putting theapparatus out of action. The time-lag device l1 includes anelectromagnet l2 which operates the switch 13 of the motor 3. The switch13 is equipped with a retarding device 14, the effect of which is thatthe switch only opens and disconnects the motor a certain interval oftime after current is cut off from the electromagnet 12. Theelectromagnet 12 can be supplied from' the battery 9. To put the drivingmechanism 3 in action the switch 10 is momentarily closed sothat thewinding 12 isexcited, attracts its armature and closes switch 13. Themotor 3 then runs so long as the retarding device holds the switch 13closed.

In Figure 2 there is also provided a so-called phonic relay 15, which isactuated by the electrical current oscillations due to speech, this isinserted in the circuit of the `time-lag device 11. This relaycomprises,

for instance, an electromagnet 16 which may be in series or in parallelwith the electromagnet S of the sound-box 2; and a contact adapted to beclosed by vibration, preferably a microphone 17, which is in the circuitof the electromagnet 12 of the time-lag device 11.

The operation of this construction is as follows If sound waves strikethe listening microphone t the electromagnet 16 of the phonic relay 15is excited. This so far diminishes the resistance of the microphonecontact 17 that the electromagnet 12 responds and the switch 13 for themotor 3 is closed. The cylinder 1 then begins to rotate, and theconversation is recorded in the usual way. It might happen that thecylinder 1 had not attained a suiiicient speed at the beginning of theconversation, so that the beginning of the record was mutilated; it istherefore desirable to provide in parallel with the microphone contact17 a switch 10 which can be inconspicuously and momentarily closedbefore conversation begins, so that the cylinder attains a sufficientspeed to record the first words clearly. So long then as sound wavesstrike the listening microphone 4t the electromagnet 12 of the time-lagdevice 11 remains eX- cited, and by it the switch 13 is held closed. Thecircuit also remains closed during pauses in the conversation, becausethe retarding device 14C prevents immediate opening of the contact 13.Only if current oscillations ceasey for some time does interruptionoccur, so that the cylinder 1 does not run uselessly.

The phonic'relay 15 with the microphone device 17 above described is anexample only of a switch device set in action by electricaloscillations.

Vfhat' I claim is:

1. A sound recording apparatus comprising in combination a recordsurface, a. motor driving said surface, electrical means including aswitch for putting said motor into and out of action, means for delayingthe opening of said switch, an electromagnet closing said switch, asource of power connected with said electromagnet, a hand operatedswitch in the circuit of said electromagnet, a contact in parallel withsaid hand operated switch adapted t0 be closed by sound vibration, andmeans for receiving sounds and recording them upon said record surface.

2. A sound recording apparatus comprising in combination a recordsurface, a motor driving said surface, electrical means including aswitch for putting said motor into and out of action, means for delayingthe opening of said switch, an electromagnet closing said switch, asource of power connected with said electromagnet, a hand operatedswitch in the circuit of said electromagnet, a microphone in parallelwith said hand operated switch, an electromagnetic sound box associatedwith said record surface to inscribe a record therein, a secondsensitive microphone separate from but connected with saidelectromagnetic sound box through said source of power, and a receivermechanically connected with said first microphone and electricallyconnected with said second sensitive microphone.

'In testimony whereof I have signed my name to this specification'.

RUDOLF HASE. Witnesses:

Lo'rHAR VVoMnR, DILLI I-ILEUFF.

